Scientific Studies of Sewage Sludge

Scientific studies of sewage sludge confirm its hazards. A list of just some of the hazardous chemicals and pathogens found in sludge can be found in the article Sludge contaminants. Sludge contaminants include Dioxins and Furans, Flame Retardants, Metals, Organochlorine Pesticides, 1,2-Dibromo-3-Chloropropane (DBCP), Naphthalene, Triclosan, Nonylphenols, Phthalates, Nanosilver, and thousands more substances.

Some select studies and technical papers are below. NOTE: A PDF version of each study is attached:

"Thousands of high production volume (HPV) chemicals are used in the US at rates exceeding 450 000 kg (1 million pounds) per year, yet little is known about their fates during wastewater treatment and upon release into the environment."
 * Randhir P. Deo and Rolf U. Halden*. In silico screening for unmonitored, potentially problematic high production volume (HPV) chemicals prone to sequestration in biosolids. Journal of Environmental Monitoring

"Any pharmaceuticals and personal care products (PPCPs) are commonly found in biosolids and effluents from wastewater treatment plants. Land application of these biosolids and the reclamation of treated wastewater can transfer those PPCPs into the terrestrial and aquatic environments, giving rise to potential accumulation in plants."
 * Wu C, Spongberg AL, Witter JD, Fang M, Czajkowski KP.. Uptake of pharmaceutical and personal care products by soybean plants from soils applied with biosolids and irrigated with contaminated water.. Environ. Sci. Technology.

"Nanosized silver sulfide (R-Ag2S) particles were identified in the final stage sewage sludge materials of a full-scale municipal wastewater treatment plant using analytical high-resolution transmission electron microscopy. The Ag2S nanocrystals are in the size range of 5-20 nm with ellipsoidal shape, and they form very small, loosely packed aggregates. This study suggests that in a reduced, S-rich environment, such as the sedimentation processes during wastewater treatment, nanosized silver sulfides are being formed. This field-scale study provides for the first time nanoparticle-level information of the Ag2S present in sewage sludge products, and further suggests the role of wastewater treatment processes on transformation of Ag nanoparticles and ionic Ag potentially released from them."
 * BOJEONG KIM, CHEE-SUNG PARK, MITSUHIRO MURAYAMA AND MICHAEL F. HOCHELLA. Discovery and Characterization of Silver Sulfide Nanoparticles in Final Sewage Sludge Products. Environ. Sci. Technology.

"Sewage sludge tests revealed 49 organohalogens present, by using methods of gas chromatography with electron capture negative ionization mass spectrometry; 23 of those were identified as flame-retardants: 'Evaluations of the risks associated with biosolids land-application...for future environmental fate'."
 * Mark J. La Guardia, Robert C. Hale, Ellen Harvey, and Da Chen. Flame-Retardants and Other Organohalogens Detected in Sewage Sludge by Electron Capture Negative Ion Mass Spectrometry. Environ. Sci. Technology, May 20, 2010. DOI: 10.1021/es9039264

Two sediment cores from a wastewater-impacted depositional zone of the Mississippi River were analyzed. 2,8-DCDD and three other dioxin congeners triclosan-derived dioxins present. The total dioxin pool "increased to as high as 31% by mass in recent years, indicating that their contribution to total dioxin toxicity may need consideration".
 * Jeffrey M. Buth, Peter O. Steen, Charles Sueper, Dylan Blumentritt, Peter J. Vikesland, William A. Arnold, and Kristopher McNeill. Dioxin Photoproducts of Triclosan and Its Chlorinated Derivatives in Sediment Cores. Environ. Sci. Technology, May 17, 2010. DOI: 10.1021/es1001105

This study shows that AC materials can catalyze transformation of secondary amines to yield trace levels of of N-nitrosamines under ambient aerobic conditions. These results show that "selecting ACs and reaction conditions are important to minimize analytical errors and undesirable formation associated with nitrosamines in water samples".
 * Lokesh Padhye, Pei Wang, Tanju Karanfil, and Ching-Hua Huang. Unexpected Role of Activated Carbon in Promoting Transformation of Secondary Amines to N-Nitrosamines. Environ. Sci. Technology. May 6, 2010, 44 (11), pp 4161–4168 DOI: 10.1021/es903916t

"The main purpose of this study was to investigate the occurrence of vancomycin resistant enterococci (VRE) in treated sewage sludge. This study 'demonstrated widespread occurrence of VRE in sewage sludge in the studied WWTP'. This indicates a “risk of antimicrobial resistance being spread to new farms and to the society via the environment if the sewage sludge is used on arable land”."
 * Leena Sahlström, Verena Rehbinder, Ann Albihn, Anna Aspan, and Björn Bengtsson . Vancomycin resistant enterococci ([[VRE]) in Swedish sewage sludge]. Acta Veterinaria Scandinavica, 2009, 51:24

The main purpose of this study was to investigate the polybrominated diphenylethers (BDEs) transfer from feed to cows’ milk. The fate of tri- to hexaBDEs in lactating cows exposed to a naturally contaminated diet was studied by analyzing feed, feces, and milk samples from a mass balance study. The behavior of the tri- to hexaBDEs was "consistent with that observed for other classes of halogenated aromatic contaminants such as PCBs and PCDD/Fs".
 * Amelie Kierkegard et. al.. A Mass Balance of Tri-Hexabrominated Diphenyl Ethers in Lactating Cows. Environmental Science & Technology, Vol. 43, No. 7, 2009

"Many of the 145 chemicals tested for were current nationwide. Biosolids from all of the 74 large treatment plants surveyed had same 27 metals, but only zinc, molybdenum, and nickel surpassed standards for application to fields. Almost all of the 11 flame retardants on the list were there in every sample."
 * Erik Stokstad. The Dirt on Sewage Sludge. Science Magazine (AAAS), January 22, 2009

"The results of this survey indicate that '27 metals were found in virtually every biosolids sample'. Four of six semivolatile organics and polycyclic aromatic hydrocarbons were found in at least 72 samples. 'All off the flame retardants except one [(BDE-138)] were essentially found in every sample; [BDE-138] was found in 54 out of 84 samples'."
 * EPA. Targeted National Sewage Sludge Survey Report. Targeted National Sewage Sludge Survey, EPA-822-R-08-014, 7 (January 2009)

"This study focuses on the investigation of agricultural soil near Decatur, Alabama., Scientists with the EPA, USDA, and FDA are investigating if perfluorinated chemicals have entered the human food chain and contaminated meat. They suspect that 'PFOA and PFOS, treated municipal sewage sludge, or biosolids, were applied to some 5000 acres of agricultural land'."
 * Rebecca Renner. EPA finds record PFOS, PFOA levels in Alabama grazing fields. Environmental Science & Technology. DOI: 10.1021/es803520c


 * Caroline Snyder. Baltimore Sludge Pilot Project Puts Children at Additional Risk.

Scientific literature of polybrominated diphenyl ethers(PBDEs) and polybrominated biphenyls(PBBs) in sewage sludge and a survey of these compounds in sewage sludge from 16 Australian wastewater treatment plants. This study presents "need for a risk assessment of PBDEs in sewage sludge used for land application".
 * Bradley Clarke et al. Polybrominated diphenyl ethers and polybrominated biphenyls in Australian Sewage Sludge. Chemosphere.2008.06.034

"Study looks at the 'fate of 14C-labelled p353-nonylphenol (NP) in soils amended with differently treated sludges originating from the same precursor'. Nonylphenol was degraded much faster in soils modified with liquid sludge, while a major portion of it was intact and extractable by organic solvents when sludge had been centrifuged prior to soil amendment."
 * V.N. Kouloumbosa, A. Schaffer, P.F.-X. Corvini. Impact of sewage sludge conditioning and dewatering on the fate of nonylphenol in sludge-amended soils. Water Research, Vol. 4 2 ( 2 0 0 8 ), pp. 3 9 4 1 – 3 9 5 1

In this study, the presence of seven pharmaceuticals and one antibacterial was evaluated using ultrasonic extraction and liquid-chromatography tandem mass spectrometry (LC–MS/MS). During the experiment…elimination was found for tetracycline, doxycycline, clindamycin, erythromycin, and clarithromycin.
 * Wu Chenxi, Alison L. Spongberg, Jason D. Witter. Determination of the persistence of pharmaceuticals in biosolids using liquid-chromatography tandem mass spectrometry. Chemosphere, 2008, 06.026

Survey looks at the use of a model wastewater treatment plant for removal of oxide nanoparticles. “Investigation on the agglomeration of oxide nanoparticles in wastewater streams revealed a high stabilization of the particles against clearance (adsorption on the bacteria from the sludge)”.
 * Limbach et al. Removal of Oxide Nanoparticles in a Model Wastewater Treatment Plant: Influence of Agglomeration and Surfactants on Clearing Efficiency. Environmental Science & Technology, 2008; 0 (0): 0 DOI: 10.1021/es800091f

"Nanoparticles should bound in the sludge and not represent a setback in the aqueous effluent. However, new study on the ceramic model material cerium dioxide found that a major “amount was able to leave an experimental sewage works and therefore could possibly enter bodies of water”."
 * Science Daily summary of Limbach paper. Nanoparticles In Sewage Could Escape Into Bodies Of Water. Science Daily, July 28, 2008

This study indicates that “The Environmental Protection Agency must gather data on the toxicity of spreading sewage sludge”. Results show that “The Environmental Protection Agency must gather data on the toxicity of spreading sewage sludge”.
 * Editorial. Stuck in the mud. Nature, p 258.

Study about a Farmer Andy McElmurray who “won his court case against the US Department of Agriculture over land poisoned by sludge fertilizer”. land poisoned by sludge fertilizer.
 * Jeff Tollefson. Raking through sludge exposes stink: Environmental Protection Agency scientists accused of fabricating data about health effects of fertilizer. Nature, p 262.

Report on the results of experiments examining the partitioning and persistence of PrPtse during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion.
 * Hinckley et al. Persistence of Pathogenic Prion Protein during Simulated Wastewater Treatment Processes. Environ. Sci. Technol. 2008, 42, 5254–5259

The purpose of this study was to test the presence and fate of Pharmaceutical and Personal Care Products (PPCP's) in the environment from three wastewater treatment facilities in Northwest Ohio, USA. The greatest number of toxic compounds "were found in the influent from the largest and most industrial wastewater treatment facility".
 * Alison L. Spongberg and Jason D. Witter. Pharmaceutical compounds in the wastewater process stream in Northwest Ohio. Science of the Total Environment, 3 9 7 ( 2 0 0 8 ) 1 4 8 – 1 5 7

Analysis of polybrominated diphenyl ethers (PBDEs) in sewage sludge after agricultural application. PBDE concentrations in sewage sludge ranged from 197 to 1185 ng/g dry weight (dw).
 * Ethel Eljarrat, Göran Marsh, Ana Labandeira, Damià Barceló. Effect of sewage sludges contaminated with polybrominated diphenylethers on agricultural soils. Chemosphere, Volume 71, Issue 6, April 2008, Pages 1079-1086

"Earthworms and soil samples were collected from three Midwest agricultural fields in order to analyze them for the presence of 77 anthropogenic waste indicators from land-applied biosolids and livestock manure."
 * Kinney et al. Bioaccumulation of Pharmaceuticals and Other Anthropogenic Waste Indicators in Earthworms from Agricultural Soil Amended With Biosolid or Swine Manure. Vol. 42, No. 6, 2008, Environmental Science & Technology

"The occurrence of five endocrine-disrupting compounds (EDCs) was tested in the treated wastewater and sewage sludge of eight sewage treatment plants (STPs) in Greece. The analytes were extracted by solid-phase extraction or sonication."
 * Athanasios S. Stasinakis, Georgia Gatidou, Daniel Mamais, Nikolaos S. Thomaidis, Themistokles D. Lekka. Occurrence and fate of endocrine disrupters in Greek sewage treatment plants. Water Research, Vol. 42 ( 2008 ) pp. 1796 – 1804

"This study analyzed the health status of residents living in Wood County, OH, near farm fields that were allowed to use biosolids. “Results revealed that some reported health-related symptoms were statistically significantly elevated among the exposed residents”."
 * Sadik Khuder et al.. Health Survey of Residents Living Near Farm Fields Permitted to Receive Biosolids. Archives of Environmental & Occupational Health, Vol. 62, No. 1, 2007

"The plasticizers bis (2-ethylhexyl) phthalate (BEHP), bis (2-ethylhexyl) terephthalate (BEHTP) and bis (2-ethylhexyl) adipate (BEHA) were found in major quantities “in the influents, process streams, treated effluent and solid residues of a large physicochemical treatment plant in Montreal, Canada”. Results obtained indicate that “the treatment plant does not effectively remove plasticizers from the influent and represents a significant source of these compounds and their degradation products in the environment”."
 * S. Barnabe´, I. Beauchesne, D.G. Cooper, J.A. Nicell . Plasticizers and their degradation products in the process streams of a large urban physicochemical sewage treatment plant. Water Research, Vol. 42 ( 2008) pp. 153 – 162

Analysis whether debromination was likely in the field; PBDE congener profiles were tracked from a wastewater treatment plant (sludge) to receiving stream sediments and associated aquatic biota.
 * Mark J. La Guardia, Robert Hale, and Ellen Harvey. Evidence of Debromination of Decabromodiphenyl Ether (BDE-209) in Biota from a Wastewater Receiving Stream. Environmental Science & Technology, Vol. 41, No. 19, 2007

This study analyzes “aerosol emission rates produced during the spreading of dewatered class B biosolids onto agricultural land”.
 * Tania Paez-Rubio et al. Emission Rates and Characterization of Aerosols Produced During the Spreading of Dewatered Class B Biosolids. Environ. Sci. Technol. 2007, 41, 3537-3544

”In this study, the presence, composition, and concentrations of organic wastewater contaminants (OWCs) were determined in solid materials produced during wastewater treatment”. Results indicate the need to better analyze the composition of OWCs in biosolids.
 * Kinney et al. Survey of Organic Wastewater Contaminants in Biosolids Destined for Land Application. Environmental Science & Technology, Vol. 40, No. 23, 2006, pp 7207-7215.

"This study examines the peer reviewed literature and official governmental reports for the presence of organic chemicals in the sludge as there are no requirement to test sewage sludges for the presence of organic chemicals in the U.S."
 * Ellen Z. Harrison et al. . Organic Chemicals in Sewage Sludges. Science of The Total Environment • Volume 367, Issues 2-3, 31 August 2006, Pages 481-497

"“About 76 percent of a commonly used antimicrobial agent exits sewage-treatment plants as a component of the sludge that's often used as a farm fertilizer”, according to the study used to track the chemical through a plant. These results raise a question to the ultimate fate of the antimicrobial in the environment"
 * Aimee Cunningham. Tainted by Cleanser. Science News, Vol. 169, No. 18, May 6, 2006, pp. 275

"Study results indicate that “approximately three-quarters of the mass of TCC disposed of by consumers in the sewer shed of the plant is released into the environment by application of municipal sludge (biosolids) on land used in part for agriculture”."
 * Heidler et al. Partitioning, Persistence, and Accumulation in Digested Sludge of the Topical Antiseptic Triclocarban during Wastewater Treatment. Environ. Sci. Technol. 2006, 40, 3634-3639.

"This study focuses on the presence of a wide range of pharmaceuticals in fresh and marine waters. “…much of the research in the area currently focuses on the removal of pharmaceuticals during sewage treatment processes…”"
 * Jonathan P. Bound and Nikolaos Voulvoulis. Household Disposal of Pharmaceuticals as a Pathway for Aquatic Contamination in the United Kingdom. Environmental Health Perspectives, Vol. 113, No. 12, Dec., 2005, pp. 1705-1711

"The purpose of this study was to evaluate if experimental exposure of pregnant sheep to a mixture of environmental chemicals…exerted effects on fetal testis development or function; application of sewage sludge was undertaken so as to maximize exposure of the ewes to its contents”."
 * Catriona Paul, Stewart M. Rhind, Carol E. Kyle, Hayley Scott, Chris McKinnell, Richard M. Sharpe. Cellular and Hormonal Disruption of Fetal Testis Development in Sheep Reared on Pasture Treated with Sewage Sludge. Environmental Health Perspectives, Vol. 113, No. 11 (Nov., 2005), pp. 1580-1587; Published by the National Institute of Environmental Health Sciences (NIEHS)

"”Possible sources of 12 organophosphorus flame retardants and plasticizers, some of which are reported to be toxic to aquatic organisms, were investigated in samples of influents, effluents, and sludge from 11 Swedish sewage treatment plants”."
 * Anneli Marklund, et al. Organophosphorus Flame Retardants and Plasticizers in Swedish Sewage Treatment Plants. Environmental Science & Technology, 2005, 39, 7423 - 7429.


 * Caroline Snyder, The Dirty Work of "Recycling" America's Sewage Sludge (2005)

"Adsorption of bisphenol-A, 17b-estradiole and 17a-ethinylestradiole to activate and to inactivated sludge from wastewater treatment plants (WWTPs) was investigated, thus allowing to distinguish between pure adsorption and biosorption."
 * Manfred Clara, Birgit Strenn, Ernis Saracevic, Norbert Kreuzinger. Adsorption of bisphenol-A, 17b-estradiole and 17a-ethinylestradiole to sewage sludge. Chemosphere 56 (2004) 843–851

"Wastewater treatment releases pollutants present in industrial and residential discharges. “The recycling of sewage sludge (also known as “biosolids”) as a soil amendment presents additional challenges to the wastewater industry, as they must now also assure these complex materials do not adversely effect the environment”."
 * Mark J. La Guardia, Robert C. Hale, Ellen Harvey, Elizabeth O. Bush,. Organic Contaminants of Emerging Concern in. Journal of Residuals Science & Technology, Vol. 1, No. 2, April 2004

This review looks at the effects of land application of contaminated waste products. Toxic metals in sewage sludges applied to agricultural land are used to “illustrate that metal behavior in soils and plant uptake is difficult to generalize because it is strongly dependent on the nature of the metal, sludge, soil properties and crop”.
 * M.B. McBride. Toxic metals in sewage sludge-amended soils: has promotion of Advances in Environmental Research, Volume 8, Issue 1, October 2003, Pages 5-19

"Purpose of this study was to evaluate different airborne bacterial endotoxin in sewage treatment plants. Results show that “higher values can be recorded during work practises where agitation of wastewater occurs."
 * Jorgen Thorn et al. Measurement Strategies for the Determination of Airborne Bacterial Endotoxin in Sewage Treatment Plants. Ann. Occup. Hyg., Vol. 46, No. 6, pp 549-554, 2002

"“The behavior of fluoroquinolone antibacterial agents (FQs) during mechanical-biological wastewater treatment was studied by mass flow analysis”. The fate of FQs in agricultural soils after sludge application was also investigated."
 * Eva M. Golet, et al. Environmental Exposure Assessment of Fluoroquinolone Antibacterial Agents from Sewage to Soil. Environmental Science & Technology, VOL. 37, NO. 15, 2003

"“The current approach to addressing health and ecosystem risks from biosolids, or sludge, requires identification of so-called “safe” or “acceptable” levels of exposure and installation of controls to achieve such levels.” There is a need to “understand and address risks of biosolids contamination, we present a new, preventative paradigm for addressing the hazards of sludge”."
 * Joel Tickner and Sara Wright. Primary Prevention Of Chemical Contamination. New Solutions, Vol. 12(4) 425-433, 2002

"This study analyzes the impact of pharmaceuticals drugs on the environment. “There is an increased presence of human and animal drugs, including hormones, antibiotics, and antineoplastic compounds in soil, lakes, rivers, and tap water”."
 * Christopher T. Nidel. Regulating the Fate of Pharmaceutical Drugs: A New Prescription for the Environment. Food & Drug Law Journal, Vol. 58, 2003, pp. 81-102

Survey on the “occurrence of pharmaceuticals, hormones, and other organic wastewater contaminants (OWCs) in water resources”. Concentrations of 95 OWCs were measured in water samples from a network of 139 streams across 30 states during 1999 and 2000.
 * Kolpin et al., 2002 D.A. Kolpin, E.T. Furlong, M.T. Meyer, E.M. Thurman, S.D. Zaugg and L.B. Barber et al. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999–2000: a national reconnaissance. Environ Sci Technol 36 (2002), pp. 1202–1211

"Analysis of fertilization of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and small amounts of industrial and household chemicals."
 * David L. Lewis, David K. Gattie, Marc E. Novak, Susan Sanchez, Charles Pumphrey. Interactions Of Pathogens And Irritant Chemicals In Land-Applied Sewage Sludges (Biosolids). BMC Public Health 2002, 2:11

“A method for the quantitative determination of humanuse fluoroquinolone antibacterial agents (FQs) ciprofloxacin and norfloxacin in sewage sludge and sludge-treated soil samples was developed”.
 * Eva M. Golet, Adrian Strehler, Alfredo C. Alder, and Walter Giger. Determination of Fluoroquinolone Antibacterial Agents in Sewage Sludge and Sludge-Treated Soil Using Accelerated Solvent Extraction Followed by Solid-Phase Extraction. Anal. Chem. 2002, 74, 5455-5462

“…potentially hazardous substances, like mercury, solvents, and pharmaceutical compounds, are introduced into the waste stream and ultimately into sewage sludge”.
 * Ted Schettler. Sewage Sludge - Looking Upstream: The Precautionary Principle. New Solutions, Vol. 12(4) 355-358, 2002

"“…U.S. Geological Survey (USGS) scientists found that biosolids contain relatively high concentrations (hundreds of milligrams per kilogram) of the active ingredients commonly found in a variety of household products and drugs”." “Spreading sewage sludge on land is but the latest in the compounding of environmental damage from sewerage. This practice must be banned and there must be a federal reorientation of all technology dealing with human excreta and the waste materials from industry and society that now are carried away by sewers”.
 * U.S. Geological Survey. Household Chemicals and Drugs Found in Biosolids from Wastewater Treatment Plants The 25 Chemicals Found in All Nine of the Biosolids Studied What's in Our Wastewaters and Where Does it Go?
 * Abby Rockefeller. Sewers, Sewage Treatment, Sludge: Damage Without End. New Solutions, Vol. 12(4) 341-346, 2002.

High concentrations of several problematic compounds have been detected in biosolids. These results and other findings call into question the EPA’s assessment’s certainty”.
 * Robert C. Hale and Mark J. LaGuardia. Have Risks Associated with the Presence of Synthetic Organic Contaminants in Land-Applied Sewage Sludges Been Adequately Addressed?. 12 New Solutions: J. Env. & Occupational Health Policy 371, 372 (2002).


 * R. Clapp and L. Orlando, eds. The Sludge Report: A special issue of New Solutions: A Journal of Environmental and Occupational Health Policy. Volume 12, Number 4, 2002.

The majority of U.S. sewage sludges are disposed by application to land for use as a soil amendment. “…the potential for off-site movement of chemicals, pathogens, and biological agents suggests that their use should be eliminated”.
 * Ellen Z. Harrison and Summer Rayne Oakes. Investigation Of Alleged Health Incidents Associated With Land Application Of Sewage Sludges. New Solutions, Vol. 12(4) 387-408, 2002


 * Hale, R.C., M.J. LaGuardia, E.P. Harvey, M.O. Gaylor, T.M. Mainor, and W.H. Duff. Persistent pollutants in land applied sludges. Nature 412:140-141.

“Disposal of sewage sludge by application to agricultural and other land is widely practised and is presumed to be environmentally beneficial, but we have found high concentrations of an environmentally persistent class of organic pollutants, brominated diphenyl ethers (BDEs), in ‘biosolids’ from four different regions of the United States”.

Related SourceWatch articles

 * biosolids
 * sewage sludge
 * Sludge contaminants